Morphobiometrical characteristics of indigenous chicken ecotype populations in Rwanda.

The rational of conservation and sustainable use of indigenous chicken (IC) resources requires their morphobiometrical characterisation. This study morphobiometrically characterised the IC ecotypes in Rwanda. The morphological features and zoometric measurement data were randomly collected on 1670 mature IC of both sexes from five ecotypes of Rwanda. The nonparametric Kruskal-Wallis and Mann-Whitney U test were used in evaluating the effect of ecotypes on the qualitative morphological variables. Zoometric measurements were analysed with the PROC GLM of SAS. The findings showed that the feather morphology and distribution were mainly normal (98.3 and 84.40%, respectively) while feather colour was dominated with multicoloured (38.10%). The majority of the birds had red earlobe (49.20%), yellow shanks (53.80%) and single comb-type (71.70%). These parameters were different (p < 0.05) between the ecotypes. Bodyweight and linear body measurements were highly different (P < 0.001) between ecotypes. Differences associated with sex (P < 0.001) were observed in body weight and linear body measurements. The interaction between ecotype and sex significantly (P < 0.001) influenced body weight, body length, shank length, comb length, comb height, wattle length, chest circumference, neck length and wingspan. The IC ecotypes in Rwanda were found to be diverse morphobiometrically both in quantitative and qualitative traits. These variations provide a foundation for classification of the chicken into breeds.

Effect of dietary antioxidant supplementation on the oxidative status of plasma in broilers.

In this study, the effect of dietary antioxidants on the plasma oxidative status of growing birds fed a diet rich in polyunsaturated fatty acids was investigated. One-day-old broilers were fed for 42 days a diet containing 4% linseed oil and supplemented with single plant extracts rich in antioxidants (natural tocopherols, rosemary, grape seed, green tea, tomato) or a combination of some of these plant extracts, in two different total doses (100 and 200 mg product/kg feed). A diet with synthetic antioxidants with and without α-tocopheryl acetate (200 mg/kg feed) were also included. The plasma oxidative status was evaluated measuring the ferric reducing ability of plasma (FRAP), the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Lipid peroxidation was measured by thiobarbituric acid-reactive substances (TBARS). No significant effect of the dietary treatments was observed for FRAP as well as for TBARS. However, diet affected GSH-Px activity (p = 0.002) and a trend for an effect on SOD activity was observed (p=0.084). A higher GSH-Px activity was found for 200 mg/kg tomato extract and natural α-tocopherol in relation to the corresponding 100 mg/kg treatment, and the lowest GSH-Px activity was measured for the synthetic antioxidants treatment. The lowest and highest SOD activity were found for the 200. and 100 mg/kg treatment with tomato extract respectively. In conclusion, the oxidative status and lipid oxidation of plasma in broilers was not affected by feeding natural antioxidant extracts at the doses in the present study, but some changes in antioxidant enzyme activities were observed, of which the implication remains to be elucidated.

Genetic parameters for intramuscular fatty acid composition and metabolism in pigs.

The aim of this study was to estimate genetic parameters for pork intramuscular fatty acid (FA) composition and indices for desaturase and elongase activities involved in n-3 and n-6 PUFA metabolism. The LM of 437 slaughter pigs was analyzed for FA composition (expressed as g/100 g of FA). Indices for enzyme activities were calculated from product to precursor FA ratios. Genetic parameters were estimated with single- and multi-trait animal models. The total FA content, reflecting the intramuscular fat content, was either included or not in the model. Results from the models without total FA content showed relatively high heritability estimates, generally above 0.50, for the proportion of the most important MUFA and PUFA, compared with much smaller values for the SFA. When total FA content was included in the models, heritability values decreased (P < 0.001) for most individual FA and for all sums of FA groups, except for C18:0, C18:3n-6, and C18:3n-3. Heritability estimates for the ratios C20:4n-6/C18:2n-6 and C22:6n-3/C18:3n-3, reflecting the overall conversion in the n-6 and n-3 PUFA pathway, respectively, were 0.29 and 0.35, respectively, with total FA content in the model and increased to 0.38 and 0.49, respectively, if total FA content was not in the model. Heritabilities for other more specific indices were of the same order. Genetic correlations between PUFA proportions and indices for enzyme activities with ADG were mostly negative, whereas the correlations with carcass lean meat percentage were mostly positive. It was concluded that there is meaningful genetic variation for long-chain PUFA metabolism that is only partly dependent on the carcass and muscle fat content. This may allow selection for improved FA composition of pork.